Comparison of Mortality Outcomes in Acute Myocardial Infarction Patients With or Without Standard Modifiable Cardiovascular Risk Factors

Abstract

BackgroundAcute myocardial infarction (AMI) cases have decreased in part due to the advent of targeted therapies for standard modifiable cardiovascular disease risk factors (SMuRF). Recent studies have reported that ST-elevation myocardial infarction (STEMI) patients without SMuRF (termed “SMuRF-less”) may be increasing in prevalence and have worse outcomes than “SMuRF-positive” patients. As these studies have been limited to STEMI and comprised mainly Caucasian cohorts, we investigated the changes in the prevalence and mortality of both SMuRF-less STEMI and non-STEMI (NSTEMI) patients in a multiethnic Asian population.MethodsWe evaluated 23,922 STEMI and 62,631 NSTEMI patients from a national multiethnic registry. Short-term cardiovascular and all-cause mortalities in SMuRF-less patients were compared to SMuRF-positive patients.ResultsThe proportions of SMuRF-less STEMI but not of NSTEMI have increased over the years. In hospitals, all-cause and cardiovascular mortality and 1-year cardiovascular mortality were significantly higher in SMuRF-less STEMI after adjustment for age, creatinine, and hemoglobin. However, this difference did not remain after adjusting for anterior infarction, cardiopulmonary resuscitation (CPR), and Killip class. There were no differences in mortality in SMuRF-less NSTEMI. In contrast to Chinese and Malay patients, SMuRF-less patients of South Asian descent had a two-fold higher risk of in-hospital all-cause mortality even after adjusting for features of increased disease severity.ConclusionSMuRF-less patients had an increased risk of mortality with STEMI, suggesting that there may be unidentified nonstandard risk factors predisposing SMuRF-less patients to a worse prognosis. This group of patients may benefit from more intensive secondary prevention strategies to improve clinical outcomes.

Management and outcomes of patients admitted with type 2 myocardial infarction with and without standard modifiable risk factors

“…The reported outcomes of SMuRF-less patients are conflicting. A study of 3081 STEMI patients by Vernon et al found SMuRF-less patients had a higher mortality compared to SMuRF patients, in agreement with other studies of STEMI patients [3,5,16,18]. Similarly, our analysis shows SMuRF-less patients presenting with T2AMI had increased risk of mortality, MACCE and stroke.…”

“…We report several important findings. Firstly, the proportion of SMuRF-less patients presenting with T2AMI (7.6%) is lower than has been reported in T1AMI studies (14-27% for STEMI and 3.7% to 23% for NSTEMI) [2,3,5,15,16]. Secondly, SMuRF-less patients were more likely to be younger, white, and female with fewer comorbidities than SMuRF patients.…”

“…In our study of T2AMI patients, we found that SMuRF-less patients were more likely to be female, white and younger with generally less comorbidities. Ethnic minority groups have previously been shown to have increased rates of diabetes mellitus, hypertension and hypercholesterolaemia when presenting with AMI, thus explaining the lower prevalence of non-white patients in the SMuRF-less cohort [2,15,20], and vice versa, the lower rates SMuRF individuals from many Asian backgrounds [16]. The majority of studies on T1AMI cohort have shown SMuRF-less patients are either a similar age or older than SMuRF patients [2,3,5,16,20].…”

“…Ethnic minority groups have previously been shown to have increased rates of diabetes mellitus, hypertension and hypercholesterolaemia when presenting with AMI, thus explaining the lower prevalence of non-white patients in the SMuRF-less cohort [2,15,20], and vice versa, the lower rates SMuRF individuals from many Asian backgrounds [16]. The majority of studies on T1AMI cohort have shown SMuRF-less patients are either a similar age or older than SMuRF patients [2,3,5,16,20]. Consistent to this study, an analysis of Asian T1AMI cohort showed SMuRF-less patients were younger compared to their counterparts [18].…”

Prediction models for major adverse cardiovascular events following ST-segment elevation myocardial infarction and subgroup-specific performance

“…Previous studies have demonstrated that multiple risk factors and their interactions are associated with the long-term prognosis of patients with STEMI treated with primary PCI ( 7 , 8 ). Patients with STEMI who are stratified into subgroups according to these risk factors have distinct clinical profiles, resulting in different MACEs risks ( 9 – 11 ). Therefore, additional subgroup-specific evaluation to predict the long-term prognosis of patients following STEMI is required to achieve effective management in different patient subgroups.…”